Combustion regulator



Aug. 25, 1936. G. wuNscH 'ET Al. 2,052,375

COMBUSTION REGULATOR Filed July l2, 1932 Patented 'Aug. 25, 1936 COIHBUSTION REGULATOR Guido Wnsch, Berlin-Steglitz, Germany, and

Herbert Ziebolz, Chicago, Ill., asslgnors to Askania-Werke A. G. vormals Central Werkstatt Dessau und Carl Bamberg-Friedman, a German Company Application July 12, 1932, Serial No. 622,168

2 Claims. (Cl. 236-45) This invention relates to regulating apparatus for controlling combustion in furnaces and the like and, among other objects, aims to provide improved regulating mechanism which is operated in accordance with changes in the composition of burnt gases or burnt gas constituents to control the supply of fuel or air or both fuel and air. i

Other aims and advantages of the invention will appear in the specification, when considered in connection with the accompanying drawing, wherein the figure is a diagrammatic view of one illustrative embodiment of the invention used for regulating or governing combustion in iiuid fuel furnaces. Referring particularly to the dra-wing, a gas furnace is shown to illustrate the invention but said invention is equally applicable to the regulation of the air supply in furnaces using liquid or solid fuel. In this illustrative embodiment of the invention the proportion of gas and combustion air is adjusted in accordance with the content of some constituent or constituents of the burnt or combustion gases, for example with the carbon dioxide content thereof, with the assistance of an electrical governing device. Referring to said figure, the gas conduit 92 is sup- `plied with combustion air through a tube l94, the

gas and air mixture thus produced entering the combustion chamber 96 of the furnace. The quantity of combustion air thus supplied is controlled or determined by a throttle valve 98 adjustment of which is effected through a link and lever connection |00, |02 with a piston |04 working in a cylinder |06. Above and below said piston. |04, said cylinder is connected by pipes |08, I0 with the interior of a casing I2 through ports 4, H6. Within said casing there is pivoted at ||8 for swinging movement in the plane of said two ports, a jet nozzle |20 having its discharge mouth adjacent said ports, said nozzle being supplied with pressure iiuid through pipes |22, |24 connected with any suitable source of supply (not shown). l

A diaphragm chamber |26 is'provided with a diaphragm |28 which is adapted to act upon said the general direction of the pivotal point of the other. Between the nozzle |20 and the lever |44 there is provided a contact member |48 adapted to be adjusted longitudinally of said lever and nozzle, said contact member |48 being connected 5 by a link |50 with the piston rod |58 of a piston operating in a cylinder |62 for that purpose.

If the contact member |48 be moved toward the pivotal point |46 of said lever |44, the action of the diaphragm |40 upon the nozzle 20 will be 10 increased, said action being decreased upon movement of said contact member |48 in thexopposite direction. Pipes |64, |66 connect the diaphragm chamber |38 at opposite sides of said diaphragm |40 with the tube 92 at opposite sides of a con- 15 striction or orice plate |68 within said tube.

It will be seen from the above that said nozzle |20 is subjected to the opposed actionloi the pressure differentials produced at the orifice plates |36 and |68, said pressure differentials being as is 20 well known proportional to the squares of 'the amounts of gas or air flowing through the tubes 92 and 94. The throttle valve 98 will therefore be so adjusted that, in proportion to the amount of gas supplied to the combustion chamber 96 25 through the tube 92, a corresponding amount ol' combustion air will always be supplied through the tube 94. In order to utilize the combustion gas in the most eiiicient manner and to the greatest advantage, it is not enough always to maintain the same proportion oi combustion air to the proportion of gas supplied. On the contrary this proportion must be varied from time to time as the composition of the combustible gases changes, because different amounts of combus- 35 tion air will be required corresponding to possible variations in the composition of the combustible gases. In order that combustion may at all times be at the highest point of emciency, the burnt gases must show a definite composition, and particularly a definite per cent content of certain constituents such as carbon dioxide.

For this purpose there is provided in the illustrative embodiment of the invention a burnt gas tester |10 which delivers an electric current value corresponding to the carbon dioxide content of the burnt gases. Herein said burnt gas tester lcomprises a plurality of fine wires |12, |14 on matter. The wires |10, |18 which, like the wires |12, |14, are electrically heated by batteryll,

are cooled more'or less by the burnt gases passt ing over them according to the carbon dioxide content of said gases.' The bridge current flows over the wires 20 202 through a coil l of a governing device 02 which herein is constructed and operates exactly like that of Fig. 1, and said bridge current; varies therefore in accordance with the variation in the carbon dioxide content of the burnt gases. The governing device 02 converts said bridge current into a pressure proportional thereto within a dlaphragm chamber 60. This pressure is conveyed through pipe 58 to' a regulator, preferably a Jet nozzle regulator constructed and operating like that shown in Fig. l. vSaid regulator comprises a diaphragm chamber 40 containing a diaphragm l0. The latter acts through a link 52 upon a jet nozzle 30 pivoted at 40 within a casing 36 so as to cause its mouth to swing in the plane of two ports 32-and 34 connected to pipes 204, 206 opening into the cylinder |62 at opposite sides respectively of the piston |60. An adjustable spring 54 acts upon the nozzle 38 in opposition to the action thereon of the diaphragm 50.

From the above it will be apparent that if the .composition of the burnt gases changes the bridge current in the conductors |12, |14 will also change as will consequently the pressure within the chamber 60 of the electrical govern-` ing device 62. As a result of this-the jet nozzle 38 will swing through a corresponding arc and by the consequent movement of the piston |60 the contact member |48 will be moved until by the thus eifected change in the proportions of gas and air in the tubes 92, 94 the correct composition of the burnt gases, predetermined by adjustment of the spring, shall be restored.

'I'his control by means of or in accordance with the carbon dioxide content of the burnt gases is a corrective control. It is therefore preferable not to allow said control to operate continuously. Accordingly an intermittently operated valve 44 may be employed in either one of the pipes 204, 206 leading to the cylinder |02 for this purpose. This valve 44 would open and close at intervals in a well known manner.

In the example shown there is disclosed the combination of an electrical governing device with an electrical burnt gas tester which delivers 'relatively weak electrical current impulses devalues by the electrical governing device and are,

available for regulating purposes. It will be apparent that in' place of the carbon dioxide content measurer herein used. any other electrical burnt gas tester could be used without departing from the-spirit of the invention. For example, a burnt gas tester which measures the free oxygen content of the burnt gases may be em' ployed. y

vIt willbe apparent to those skilled in the art that the vpresent invention may be embodied in other specific forms without departing from the 'spirit or essential attributes thereof, and it is therefore desired that the present embodiment of said invention be considered in all respects as illustrative and not restrictive, reference being had to the appended claims ratherthan to the foregoing description to indicate the scope of the invention. f

We claim:

l. Combustion control apparatus for a furnace having conduits for delivering fuel and air comprising, in combination, a valve in at least one of said conduits. a regulator connected to operate said valve in response to the flow of fuel and air in said conduits to control the ratio of fuel and air; a ratio varying member in said regulator; and a combustion tester for the products of combustion from the furnace connected to vary the setting of said ratio varying member and thereby maintain the proper ratio between the fuel and air.

2. Combustion control apparatus for a furnace having conduits for delivering fuel and air comprising, in combination, a valve in one4 of said conduits; a regulator connected to operate said valve in response to the flow of fuel and air in said conduits to control the ratio of fuel and air; means responsive to the carbon dioxide content of the furnace combustion products to create proportional governing impulses; a governing device connected to be controlled by said vmeans and converting said impulses into proportional :duid pressure impulses; a ratio varying member in said regulator; and means connecting said governor to actuate said ratio varying member in response to said uid pressure impulses, whereby the carbon dioxide content in the products of combustion is maintained substantially constant.

GUmo w'NscH..

mi' M' ZIEBOLZ. 

